Question

当值为＆＃34;完成时，我尝试在我的数据库中获取所有对象＆＃34;但我得到一个例外。我认为我的查询是正确的，因为我在另一种方法中使用相同的查询来仅恢复对象。

populate

我的例外：

public List<DownloadProfile> getAllDownloadProfile(String state) {
    List<DownloadProfile> downloadProfiles = new ArrayList<>();
    Cursor cursor = db.rawQuery("SELECT * FROM " + DownloadEntry.TABLE_NAME
            + " WHERE " + DownloadEntry.COLUMN_NAME_DL_STATE + " = " + state + "", null);

    if (cursor.getCount() > 0) {
        cursor.moveToFirst();
        do {
            DownloadProfile downloadProfile = new DownloadProfile(-1, "", "", "");
            downloadProfile.path = cursor.getString(cursor.getColumnIndex(DownloadEntry.COLUMN_NAME_DL_PATH));
            downloadProfile.extension = cursor.getString(cursor.getColumnIndex(DownloadEntry.COLUMN_NAME_DL_EXTENSION));
            downloadProfile.downloadId = cursor.getInt(cursor.getColumnIndex(DownloadEntry.COLUMN_NAME_DL_ID));
            downloadProfiles.add(downloadProfile);

        } while (cursor.moveToNext());
    }
    cursor.close();
    return downloadProfiles;
}

Answer 1

SQL中的字符串文字进入'single quotes'。不带引号的字符串被解释为标识符，例如列名。

但是，最好使用?变量并绑定值：

Cursor cursor = db.rawQuery("SELECT * FROM " + DownloadEntry.TABLE_NAME
        + " WHERE " + DownloadEntry.COLUMN_NAME_DL_STATE + " = ?", new String[] { state });

我尝试在数据库android sqlite中获取所有对象时出错

1 个答案: